Packaging material for electronic-part case, and others

ABSTRACT

The present invention provides a casing material for an electronic component which has a good adhesion with an aluminum foil and a resin layer, impermeability of steam, heat seal property, and corrosion resistance for an electrolyte. The present invention also provides a casing for an electronic component using the casing material. The present invention also provides an electronic component including the casing. The casing material comprises a heat resistant resin drawn film layer as an outer layer, a thermoplastic resin not-drawn film as an inner layer, and an aluminum foil layer provided between the layers. In particular, an acrylic polymer layer is provided between the aluminum foil layer and the not-drawn film layer.

TECHNICAL FIELD

[0001] The present invention relates to a casing material for anelectronic component, which can be used as a casing for an electroniccomponent such as a lithium ion battery and a capacitor. It also relatesto a casing for an electronic component, an electronic componentequipped with the casing and a packaging material.

BACKGROUND ART

[0002] In recent years, electric equipment such as voice equipment andvisual equipment has become small, light and thin. Especially, in the OA(Office Automation) field, a personal computer has been miniaturized,e.g., from a desktop type to a notebook type, and a memory card has beendeveloped. Furthermore, the aforementioned electric equipment isdesigned to be connected with a cellular phone.

[0003] As electronic apparatus has become small and light, a secondarybattery and/or capacitor are required to have an improved performanceand lightweight. To cope with the aforementioned requests, a secondarybattery has been changed from a conventional lead storage battery to anickel-cadmium battery or a lithium battery having high energy density.Recently, a lithium-ion secondary battery and a nickel-hydrogensecondary battery have become popular. Thus, the development in thisfield has been made quickly. Furthermore, an electrical double layercondenser, which can be used as a power supply of a hybrid car becauseof its high volume energy density, durable charge-and-dischargeperformance, is being put in practical use.

[0004] A secondary storage battery is required to be charged anddischarged repeatedly. In this secondary storage battery, if moisture ismixed therein at the time charging, hydrolysis of the electrolyte and/ororganic solvent may occur. Furthermore, if oxygen and/or moisturecontained in the ambient air are introduced into the battery,deterioration and/or decomposition of the positive active material,negative electrode active material and/or conductive polymer may occur.Accordingly, the casing for an electronic component is required to bestrictly sealed. The similar requirement is applied to an electroniccomponent, such as an electric double layer condenser containingnon-basin electrolyte.

[0005] To cope with such requirements of lightweight and sealing, it hasbeen proposed that a laminated member laminating a thermoplastic resinfilm and an aluminum foil is used as a casing material for an electroniccomponent.

[0006] For example, Japanese Unexamined Laid-open Patent PublicationS59-173944 (hereinafter referred to as “JP59-173944”) proposes a casingmaterial for an electronic component. In the casing material, analuminum thin foil is covered by a resin film, or an aluminum thin foilis sandwiched between resin films.

[0007] Japanese Unexamined Laid-open Patent Publication H8-83596(hereinafter referred to as “JP8-83596”) proposes to utilize alamination of polyethylene film/aluminum film/polyethylene film as acasing material for a thin card-shaped battery.

[0008] Japanese Unexamined Laid-open Patent Publication H9-213285(hereinafter referred to as “JP9-213285′) proposes a casing material foran electronic component. The casing material has a multi-layer structureincluding at least one aluminum foil layer as an inner layer, and isformed into a cylindrical shape.

[0009] Japanese Unexamined Laid-open Patent Publication H10-157008discloses a lamination film of polyethylene film/aluminum foil/hot meltlayer/oriented polyester film. The publication also proposes to obtain abattery casing by thermally forming the laminated film. It is thoughtthat a polyester film of copolymerization polyester having goodthermoforming nature is preferably used as the aforementioned polyesterfilm.

[0010] The aforementioned casing material as taught by JP59-173944 isformed by heat-pressing the end portions of a laminated member in whichan aluminum foil having a thickness of 20 μm is sandwiched betweenpolyethylene layers each having a thickness of 100 μm. The sealing isperformed by heat-sealing the casing material. The casing material astaught by JP8-83596 is used as a casing material for a thin card-shapedelectronic component. This casing material requires a large sealingportion (a heat sealed portion of external casing materials so as not toallow an invasion of air or moisture into an inside of battery) at anexternal peripheral portion of a power generation component of abattery. The ratio of the area and volume of the sealing portion tothose of the entire battery is large, which impedes to increase thevolume energy density of the battery.

[0011] Furthermore, according to the teaching of JP9-213285, thealuminum laminated member is formed into a cylindrical shape, then apower generation element is inserted into the cylindrically formedcasing. Then, the lower and upper openings thereof are sealed by heatsealing or adhesive agent. Thus, the sealing area can be halved, and thevolume energy density can be increased as compared with theaforementioned casing for a thin card-shaped electronic component.However, it must be said that the energy density is still inadequate.

[0012] The casing material as taught by JP10-157008 is to be subjectedto heat forming. Since polyethylene is used as the materials of theinner film, it is difficult to satisfy the high temperature preservationexamination (safety examination) of a battery requiring enough bondingstrength at high temperature. In order to thermally forming it, it ispreferable that the polyester film is a polymerization polyester film.On the other hand, since the oriented polyester film is inferior inadhesive performance, it thermally contracts at the time ofthermoforming and cannot obtain sufficient bonding strength by a normaldry laminating adhesive. Thus, it is required to use hot-melt adhesiveagent.

[0013] Furthermore, in place of the conventional aluminum casing with avinyl chloride resin cover, a casing made of thermoplastic nylonlamination and aluminum materials (see Japanese Unexamined Laid-openPatent Publication No. H8-001857) or thermoplastic-polyester resinpainted aluminum materials (see Japanese Unexamined Laid-open PatentPublication No. H9-275043) has become available. Thus, materials havebeen developed to decrease the weight and avoid the use of vinylchloride resin.

[0014] Furthermore, another capacitor casing material has been proposed(see Japanese Unexamined Laid-open Patent Publication No. 2001-011658).The casing material includes an aluminum foil having a roughenedsurface, a chemical coating formed on the roughened surface and anorganic resin covering formed on the coating.

[0015] In order to obtain a battery with high volume energy density thatcan be mounted in a miniaturized and thinned housing of an electronicapparatus, the casing of the battery is required to have a shapecorresponding to the available space of the printed circuit board sothat it can be fitted in the space without casing any dead space. Inorder to meet the aforementioned requirements, it is required that thecasing is thin and has a sharp shape. Therefore, it is required that thealuminum foil laminated member is thinner, and can be formed into adesired shape sharply.

[0016] Judging from this point of view, since the aforementionedconventional material for a battery casing has, for example, a structureof polyethylene film (100 μm)/aluminum foil (20 μm)/polyethylene film(100 μL m) or polypropylene film (100 μm)/aluminum foil (20μm)/polypropylene film (100 μm), the formability thereof is notsatisfactory. Thus, the material cannot be used as it is.

[0017] Another proposal has been made. In this proposal, the casing foran electronic component has a structure of heat-resistant-resin orientedfilm/aluminum foil/polyolefine film, acid denaturized polyolefine filmor ionomer resin film from the surface. This casing is thin and good informability, and can dissolve almost all of the aforementioned problems.However, polyolefine, acid denaturized polyolefine or ionomer resincannot assuredly prevent permeation of non-water-electrolysis liquid ofa lithium battery, to thereby cause invasion of the aluminum foil.Furthermore, in case of using polyolefin resin, the adhesive property tothe aluminum foil becomes insufficient. Thus, it was necessary to solvethese problems. The similar problems can also be applied to a capacitorcasing of a capacitor containing non-water-electrolysis.

[0018] It is an object of the present invention to provide a casingmaterial for an electric component which is excellent in formabilitysuch as overhang forming and a deep drawing forming, excellent instrength, excellent in adhesive performance between an aluminum foil anda resin layer, excellent in impermeability of moisture, excellent inheat sealing performance, and will not be invaded by corrosiveelectrolyte.

[0019] It is another object of the present invention to provide a casingfor an electric component.

[0020] It is still another object of the present invention to provide anelectric component such as a storage battery with high volume energydensity and a capacitor equipped with the aforementioned casing.

DISCLOSURE OF INVENTION

[0021] In order to attain the aforementioned objects, the presentinventors have studied eagerly and found the fact that the objects canbe attained by providing an acrylic polymer layer between an aluminumfoil layer and a not-drawn film layer (or unoriented film layer).Furthermore, the present inventors also have found that a polymer havingat least one organic group selected from the group consisting ofhindered amino group, cycloalkyl group and benzotriazol group, eachgroup having a specific structure, can be preferably used as theaforementioned acrylic polymer layer to thereby perform remarkableeffects. Thus, the present invention has been completed.

[0022] According to a first aspect of the present invention, a casingmaterial for an electronic component, wherein the casing materialcomprises a heat resistant resin drawn film layer (or heat resistantresin oriented film layer) as an outer layer, a thermoplastic resinnot-drawn film layer (or thermoplastic resin unoriented film layer) asan inner layer and an aluminum foil layer disposed between the drawnfilm layer and the not-drawn film layer, is characterized in that: anacrylic polymer layer is provided between the aluminum foil layer andthe not-drawn layer.

[0023] It is preferable that the acrylic polymer layer is made of apolymer having at least one organic group selected from the groupconsisting of hindered amino group, cycloalkyl group and benzotriazolgroup.

[0024] It is preferable that the acrylic polymer layer comprises apolymer obtained by crosslinking an acrylic polyol with an isocyanate.

[0025] It is preferable that the aluminum foil layer is made of anO-member of pure aluminum or aluminum iron alloy having a thickness of 7to 100 μm.

[0026] It is preferable that the heat resistant resin drawn film layercomprises a drawn film made of a polyamide or polyester with a thicknessof 9 to 50 μm.

[0027] It is preferable that the heat resistant resin drawn film is 150N/mm² or more in tensile strength and 80% or more in tensile elongationof four directions (0°, 45°, 90°, 135°).

[0028] It is preferable that the thermoplastic resin not-drawn filmlayer comprises a drawn film made of a thermoplastic resin selected fromthe group consisting of polyethylene, polypropylene, olefin copolymer,acid denaturation thereof and ionomer.

[0029] The aforementioned casing for an electronic component can bepreferably used as a battery casing or a capacitor casing.

[0030] According to a second aspect of the present invention, the casingfor an electronic component may be formed by deep-drawing or overhangdrawing the aforementioned casing material for an electronic componentinto a predetermined shape.

[0031] According to a third aspect of the present invention, anelectronic component comprises: an electronic component body; and acasing surrounding the electronic component body, wherein the casing isformed by deep-drawing or overhang-drawing the aforementioned casingmaterial for an electronic component.

[0032] The aforementioned electronic component body may be exemplifiedby a battery such as a lithium ion battery, a polymer battery, a nickelhydrogen battery, a primary battery and a secondary battery.

[0033] The aforementioned electronic component body may be alsoexemplified by a capacitor such as an electrical double layer condenser.

[0034] According to a fourth aspect of the present invention, apackaging material for packaging a corrosive content, such as medicine,cosmetic, chemical for photograph and organic solvent, comprises: a heatresistant resin drawn film layer as an outer layer, a thermoplasticresin not-drawn film layer as an inner layer, and an aluminum foil layerdisposed between the layers, wherein an acrylic polymer layer isprovided between the aluminum foil layer and the not-drawn film layer.

BEST MODE FOR CARRYING OUT THE INVENTION

[0035] The casing material for an electronic component according to thepresent invention can be pressed by means of using a cold (roomtemperature) pressing method such as an overhang or deep-drawing method.According to the present invention, the casing material is strong evenif it is pressed into a thin body. Also, the casing material accordingto the present invention realizes to form accurately by such a method asan overhang method and a deep-drawing method (which is hereinafterreferred to as “pressing”). Furthermore, according to the casingmaterial, an aluminum foil is assured to adhere to a resin layer.Furthermore, the casing material according to the present invention is alaminated member having an aluminum foil, which improves inimpermeability of steam and electrolyte. Also, the casing materialaccording to the present invention prevents an aluminum foil from beingbroken or cracked due to necking at the time of forming.

[0036] The aforementioned casing material is preferably useful for acasing for a battery such as a lithium ion battery, a polymer battery ora nickel hydrogen battery, which contains significantly corrosiveelectrolyte therein and needs to strictly prevent an entering ofmoisture and/or oxygen. Furthermore, the aforementioned casing materialis also useful for a casing of a primary battery, a secondary battery orthe like which is required to reduce its weight and size, for which anaccurate and sharp formability is required.

[0037] The aforementioned casing material is also useful for a casing ofa capacitor such as an electrolytic capacitor. Also, the casing materialis preferably used as a casing of an electrical double layer capacitor,which has increased capacity, high volumetric energy density and longlifetime regardless of repetition of quick charge and dischargeoperations, and has been remarkable for an energy source since itaccompanies with less occurrence of pollution.

[0038] According to the present invention, the aluminum foil, whichconstitutes the aforementioned casing material for an electroniccomponent, may be made of any material as long as it has appropriateformability. From a viewpoint of easily pressing to form, it ispreferable to use pure aluminum or Al—Fe alloy, such as AA-8021 alloyand AA-8079 alloy. As for the thickness thereof, it is preferable to usean O-member (soft material) having a thickness of 7 to 100 μm,preferably 15 to 80 μm, to thereby assure appropriate formability andbarrier ability for preventing invasion of oxygen and/or moisture.

[0039] In case where the thickness is less than 7 μm, there may be apossibility that the aluminum foil may be unexpectedly broken or crackedat the time of pressing to form. Even if no break or crack occurs, theremay be another possibility of generating pinholes and the like thereon,to thereby raise a risk of invasion of oxygen and/or moisture into thecase. On the other hand, even if the thickness exceeds 100 μm, there maybe no more better prospect to further improve the prevention of thealuminum foil from broken or cracked at the time of pressing to form.Also, there may be no more better prospect to further improve theprevention of a pinhole from generated. Furthermore, increasing of thethickness more than 100 μm merely results in an increasing of weight anda decreasing of volumetric energy density of the resultant product.Accordingly, it is preferable that the thickness does not exceed 100 μm,but not to be limited thereto and be flexible to be varied according tothe size of the case produced.

[0040] In order to improve chemical resistance and adhesion to a resinfilm, it is preferable that the aluminum foil is treated on its surfaceby using a surface treatment agent of chromium, non-chromium (forexample, of zirconium).

[0041] In order to improve an adhesion of a layer of a resin film, thealuminum foil may be undercoated with a silane coupling agent or atitanium coupling agent, or may be subjected to a corona treatment.

[0042] In the casing material for an electronic component, in order toprevent an aluminum foil from being broken or cracked due to necking atthe time of pressing as well as to produce an accurate product, it isnecessary to laminate a heat resistant resin biaxially drawn film on atleast one of the surfaces of the aluminum foil by means of a drylaminate adhesive or the like. The aforementioned heat resistant resinfilm may be made of polyamide (nylon), polyester, polyimide andpolypropylene. Each of the materials may be high in strength, large inelongation and rich in flexibility. It is preferable that theaforementioned heat resistant resin film is made of a biaxial stretchingpolyamide.

[0043] In case of using a polyamide film or a polyester film, it ispreferable to use one having comparatively high strength, comparativelylarge elongation and less directionality as the aforementioned polyamidefilm or polyester film. Such polyamide film or polyester film as anouter layer is directly laminated on an aluminum foil, so that thealuminum foil may be prevented from necking at the time of pressing toform, so as to obtain a casing having a predetermined accurate shape.

[0044] In this case, the film is required to have a thickness of 9 to 50μm, preferably 12 to 30 μm. In case where the thickness is less than 9μm, the drawn film may be expanded insufficiently to form, therebysometimes causing necking in the aluminum foil, which results in poorforming due to break or crack generated in the aluminum foil. On theother hand, in case where the thickness exceeds 50 μm, although thestability to hold its shape may be improved, there may be no more betterprospect to further improve the prevention of breaking or cracking, orto further improve its formability. On the contrary, there may be apossibility to reduce the volumetric energy density.

[0045] It is preferable that the aforementioned heat-resistant-resindrawn film is 150 N/mm² or more in tensile strength in any of the fourdirections (0°, 45°, 90°, and 135°), preferably 200 N/mm², and that thetensile elongation in any of the four directions is 80% or more,preferably 100% or more. By using such a heat resistant resin drawnfilm, a casing has a predetermined shape even if it is not made of afilm of copolymer.

[0046] In particular, in case of using a heat resistant resin drawn filmhaving tensile strength of 200 N/mm² or more and tensile elongation of100% or more in any of the four directions, a casing having a furtheraccurate shape can be produced stably.

[0047] In cases where the tensile strength in any of the four directionsis less than 150 N/mm² or in cases where the elongation in any of thefour directions is less than 80%, there may be a possibility that thecasing material may be unexpectedly broken at its corner portion duringpressing to sharply form (breaking of the aluminum foil).

[0048] Among these heat resistant resin drawn films, a polyamide filmhas elongation larger than that of a polyester film. Accordingly, it isadvantageous to use a polyamide film in case of pressing a batterycasing whose height is deeper.

[0049] According to the present invention, a polyamide film or apolyester film, which has less directionality in terms of mechanicalproperty, may be directly laminated on an aluminum foil by means of adry laminate adhesive of urethane. Therefore, the present inventionenables to sharply form by means of a cold press method (overhang or adeep-drawing method).

[0050] Furthermore, a thermoplastic resin not-drawn film (which ishereinafter referred to as “not-drawn film or the like” forsimplification), such as a polyethylene resin film, a polypropyleneresin film, a maleic acid denatured polypropylene resin film, anethylene acrylate copolymer film and an ionomer resin film, may be usedas an inner layer material of the casing material for an electroniccomponent. Each of those materials may be used to improve chemicalresistance against strong corrosive electrolyte contained in a lithiumion secondary battery and the like, and also to assure heat sealingability to the casing material to thereby maintain the sealing of thecase.

[0051] As such a thermoplastic resin un-drawn film or the like, thefollowing materials can be used: polyethylene (PE: including highdensity, middle density or low density polyethylene, linear low densitypolyethylene, and a copolymer with alpha olefin in a small amount);polypropylene (PP: including copolymer with ethylene or anotherpolymerizable monomer in a small amount); denatured polyethylene bymaleic anhydride and the like (denatured PE); denatured polypropylene bymaleic anhydride or the like (denatured PP); or copolymer of ethylene,acrylic acid and acrylic ester (EAA) or ionomer resin, or a blendcomposition thereof. It is necessary to laminate the aforementionednot-drawn film on the aluminum foil via an acrylic polymer layer. Incases where the casing is used as a battery, it is preferable to use PPor a denatured PP having high thermal resistance. In cases where thecasing is used as a capacitor, it is preferable to use a linear lowdensity polyethylene having good fluidity at the time of heat sealed toa terminal.

[0052] Each of the materials, PP, denatured PP and EAA resin is superiorin sealing strength at high temperature. Therefore, there is a lesspossibility for a battery to leak, swell or break under a hightemperature preservation examination (safety test).

[0053] From a viewpoint of safety at high temperature, polypropylene(which has a melting point of 140 to 170° C. is most optimal to use.

[0054] On the other hand, each of those three kinds of resins, that isdenatured PE, denatured PP, and EAA or ionomer resin, has good adhesiveproperty to metal (or a metal terminal) as compared with polyethylene,polypropylene or the like. Therefore, there may be a less possibility ofcausing delamination or the like.

[0055] Therefore, it is preferable to use PP when priority is given tohigh temperature safety. On the other hand, it is preferable to use anyof a denatured PE, denatured PP and EAA or ionomer resin when inconsideration of a balance between safety and adhesion to metal. Use ofthese resins enables to give a heat-sealing to the casing materialaccording to the present invention and to obtain sufficient chemicalresistance (electrolyte resistance) and stability of form (rigidity).

[0056] It is necessary that the not-drawn film has a thickness of 10 to70 μm, preferably 20 to 55 μm. When the thickness is less than 10 μm,the resultant formed material has a thickness being too thin, to therebysometimes generate pinholes, which results in decreased corrosionresistance to electrolyte or the like. On the other hand, even if usinga film having a thickness of 70 μm or more, there may be no more betterprospect to further improve chemical resistance and heat sealingability, which on the contrary results in mere reducing of volumetricenergy.

[0057] In order to attain the aforementioned objects, the presentinventors have studied eagerly and found the fact that the objects canbe attained by providing an acrylic polymer layer between an aluminumfoil layer and a not-drawn film layer. Furthermore, the presentinventors also have found that a polymer having at least one organicgroup selected from the group consisting of hindered amino group,cycloalkyl group and benzotriazol (ultraviolet-absorbable) group, eachgroup having a specific structure, can be preferably used as theaforementioned acrylic polymer layer to thereby perform remarkableeffects. Thus, the present invention has been completed.

[0058] The present invention provides a casing material for anelectronic component excellent in impermeability of steam andelectrolyte, formability, heat sealing and the like.

[0059] According to the present invention, a polymer, which constitutesthe acrylic polymer layer provided between the aluminum foil layer andthe not-drawn film layer, can be obtained by polymerizing componentsincluding 50 mass % or more of (meth) acrylic monomer. It is morepreferable that the 80 mass % or more of (meth) acrylic monomer isincluded as the polymerizable components.

[0060] As a polymerizable monomer, the followings can be used: (meth)acrylic acid alkyl ester monomer; a polymerizable monomer having ahydroxyl group; a polymerizable unsaturated carboxylic acid monomer; apolymerizable monomer having a sulfonic acid group; an acid phosphatepolymerizable monomer; a polymerizable monomer having an epoxy group; apolymerizable monomer having a nitrogen atom; a polymerizable monomerhaving a halogen atom; an aromatic polymerizable monomer; vinyl ester;vinyl ether; a polymerizable monomer having a cyano group; a siliconmonomer; a monomer having an isocyanate group; a multi functionalmonomer; and the like. At least one monomer selected from the groupabove listed may be used.

[0061] As a (meth) acrylic acid alkyl ester monomer, the followings canbe used:

[0062] monomer having a cycloalkyl group such as cyclohexyl (meth)acrylate; methyl cyclohexyl (meth) acrylate; tert-butyl cyclohexyl(meth) acrylate; and cyclo dodecyl (meth) acrylate; methyl acrylate;ethyl acrylate; n-butyl acrylate; iso-butyl acrylate; tert-butylacrylate; sec-butyl acrylate; n-propyl acrylate; iso-propyl acrylate;isoamyl acrylate; 2-ethylhexyl acrylate; iso-decyl acrylate; tridecylacrylate; n-octyl acrylate; iso-octyl acrylate; n-lauryl acrylate;benzyl acrylate; dicyclopentanyl acrylate; n-stearyl acrylate;iso-stearyl acrylate; iso-bornyl acrylate; 2-(acetoacetoxy) ethylacrylate; phenoxyethyl acrylate; methyl methacrylate; ethylmethacrylate; n-butyl methacrylate; iso-butyl methacrylate; tert-butylmethacrylate; sec-butyl methacrylate; n-propyl methacrylate; iso-propylmethacrylate; iso-amyl methacrylate; 2-ethylhexyl methacrylate;iso-decyl methacrylate; tridecyl methacrylate; n-octyl methacrylate;iso-octyl methacrylate; n-lauryl methacrylate; benzyl methacrylate;dicyclopentanyl methacrylate; n-stearyl methacrylate; iso-stearylmethacrylate; iso-bornyl methacrylate, 2-acetoacetoxy ethyl methacrylate(Brand name: AAEM, Eastman); and phenoxyethyl meta-crylate.

[0063] As an acrylic monomer having a hydroxyl group, the followings canbe used:

[0064] 2-hydroxy ethyl acrylate; 2-hydroxy propyl acrylate; 3-hydroxypropyl acrylate; 2-hydroxy butyl acrylate; 4-hydroxy butyl acrylate(Brand name: 4HBA, Mitsubishi Chemical); α-hydroxymethyl ethyl acrylate;α-hydroxy methyl acrylate; caprolactone denatured hydroxy acrylate(Brand name: Placcel F Series made by Daicel Chemical Industries, Ltd.);2-hydroxy ethyl methacrylate; 2-hydroxy propyl methacrylate; 3-hydroxypropyl methacrylate; 2-hydroxy butyl methacrylate; and 4-hydroxy butylmethacrylate; and caprolactone denatured hydroxy methacrylate (Brandname: Placcel F Series made by Daicel Chemical Industries, Ltd).

[0065] As a monomer having an acid functional group, acrylic acid;methacrylic acid; maleic acid; fumaric acid; crotonic acid; itaconicacid; maleic anhydride; caprolactone denatured acrylate having acarboxyl group at its end; caprolactone denatured methacrylate having acarboxyl group at its end (Brand name: Placcel FMA series made by DaicelChemical Industries, Ltd.); sulfoethyl acrylate; sulfoethylmethacrylate; 2-acryloyloxyethyl acid phosphate; 2-methacryloyl oxyethylacid phosphate; 2-acryloyl oxypropyl acid phosphate; and 2-methacryloyloxypropyl acid phosphate.

[0066] As a vinyl ester, the followings can be used:

[0067] acetic acid vinyl ester; butyric acid vinyl ester; caproic acidviny ester; caprylic acid vinyl ester; capric acid vinyl ester; lauricacid vinyl ester; myristic acid viny ester; palmitic acid vinyl ester;stearic acid vinyl ester; cyclohexane carboxylic acid vinyl ester;pivalic acid vinyl ester; octyl acid vinyl ester; monochloroacetic acidvinyl ester; adipic acid divinyl ester; methacrylic acid vinyl ester;crotonic acid vinyl ester; sorbic acid vinyl ester; benzoic acid vinylester; and cinnamic acid vinyl ester.

[0068] As a silane compound monomer, the followings can be used:

[0069] vinyl trichloro silane; vinyl tris (β-methoxy ethoxy) silane;vinyl triethoxy silane; vinyl trimethoxy silane; γ-methacryloxy propyltrimethoxy silane; trimethylsiloxy ethyl methacrylate halogen; trifluoroethyl acrylate; tetrafluoro propyl acrylate; octafluoro pentyl acrylate;heptadodecafluoro decyl acrylate; β-(perfluorooctyl) ethyl acrylate;trifluoro ethyl methacrylate; tetrafluoro propyl methacrylate;hexafluoro propyl methacrylate; octafluoro pentyl methacrylate;heptadodecafluoro decyl methacrylate; β-(perfluorooctyl) ethylmethacrylate; tribromophenol EO 3 moles adduct methacrylate; andtribromo phenyl methacrylate.

[0070] As a monomer containing a fluorine atom, perfluoro octylethylacrylate and perfluoro octylethyl methacrylate can be used.

[0071] As a polymerizable monomer containing a nitrogen atom, thefollowings can be used:

[0072] a monomer having a hinderd amine group such as: 4-(meth)acryloyloxy-2,2,6,6-tetramethyl piperidine; 4-(meth)acryloyloxy-1,2,2,6,6-pentamethyl piperidine; 4-(meth)acryloylamino-2,2,6,6-tetramethyl piperidine; 4-(meth)acryloylamino-1,2,2,6,6-pentamethyl piperidine; 4-cyano-4-(meth)acryloyl amino-2,2,6,6-tetra methyl piperidine;4-crotonoyloxy-2,2,6,6-tetramethyl piperidine;4-crotonoylamino-2,2,6,6-tetramethyl piperidine; 1-(meth)acryloyl-4-(meth) acryloylamino-2,2,6,6-tetramethyl piperidine; 1-(meth)acryloyl-4-cyano-4-(meth) acryloyl amino-2,2,6,6-tetramethyl piperidine;1-crotonoil-4-crotonoiloxy-2,2,6,6-tetramethyl piperidine; and reactiveHALS which is commercially available such as Adkstab LA-82 and AdkstabLA-87 (made by Asahi Denka Kogyo K.K.), and FA-711MM and FA-712HM (madeby Hitachi Chemical Co., Ltd.);

[0073] a monomer containing a benzotriazol group such as:2-[2′-hydroxy-5′-(meth) acryloyloxy ethylphenyl]-2H-benzotriazol;2-[2′-hydroxy-5′-(meth) acryloyl oxy propyl phenyl]-2H-benzotriazol;2-[2′-hydroxy-5′-(meth) acryloyl oxy hexyl phenyl]-2H-benzotriazol;2-[2′-hydroxy-3′-tert-buthyl-5′-(meth) acryloyl oxy ethylphenyl]-2H-benzotriazol; 2-[2′-hydroxy-3′-tert-buthyl-5′-(meth) acryloyloxy ethyl phenyl]-5-chloro-2H-benzotriazol;2-[2′-hydroxy-5′-tert-buthyl-3′-(meth) acryloyl oxy ethylphenyl]-2H-benzotriazol; 2-[2′-hydroxy-5′-(meth) acryloyl oxy ethylphenyl]-5-chloro-2H-benzotriazol; 2-[2′-hydroxy-5′-(meth)-acryloyl oxyethyl phenyl]-5-methoxy-2H-benzotriazol; 2-[2′-hydroxy-5′-(meth)acryloyl oxy ethyl phenyl]-5-cyano-2H-benzotriazol;2-[2′-hydroxy-5′-(meth) acryloyl oxy ethylphenyl]-5-t-buthyl-2H-benzotriazol; and2-[2′-hydroxy-5′-(β-methacryloyloxyethoxy)-3′-tert-butylphenyl]-4-tert-buthyl-2H-benzotriazol;

[0074] acrylamides such as: acrylamide; t-butyl acrylamide; methylenebis acrylamide; methoxy methyl acrylamide; ethoxy methyl acrylamide;buthoxy methyl acrylamide; methylol acrylamide; methacrylamide;methylene bis methacrylamide; methylol methacrylamide; N-isopropylacrylamide; N-methylol acrylamide; N-methoxy methyl acrylamide;N-buthoxy methyl acrylamide; diacetone acrylamide; N, N-dimethyl aminopropyl acrylamide; N-phenyl maleimide; N-cyclohexyl maleimide;2-iso-propenyl-2-oxyazoline;

[0075] a monomer having an isocyanate group such as: 2-methacryloyloxyethyl isocyanate (Brand name: Karenz MOI made by Showa Denko K.K.);methacryloyl isocyanate (Brand name: MAI made by Nippon Paint Co.,Ltd.); m-iso-propenyl-α,α dimethyl benzyl isocyanate (Brand name: m-TMImade by Takeda Chemical Industries, Ltd.); and

[0076] imide acrylate; imide methacrylate; dimethyl amino ethylacrylate; dimethyl amino ethyl methacrylate; diethyl amino ethylacrylate; diethyl amino ethyl methacrylate; quaternary dimethyl aminoethyl acrylate; quaternary dimethyl amino ethyl methacrylate;methacryloyl oxyethyl trimethyl ammonium chloride; dimethyl amino ethylmethacrylate sulfate; morpholine EO adduct methacrylate;N-vinylpyridine; N-vinyl imidazole; N-vinyl pyrrole; N-vinylpyrrolidone; N-vinyl oxazolidon; N-vinyl succinicimide; N-vinyl methylKARUPEMATE; N, N-methyl vinyl acetamide, etc.

[0077] As a multi-functional polymerizable monomer, the followings canbe used; ethylene glycol diacrylate; diethylene glycol diacrylate;triethylene glycol diacrylate; polyethylene glycol #200 diacrylate;polyethylene glycol #400 diacrylate; polyethylene glycol #600diacrylate; polyethylene glycol #1000 diacrylate; 1, 3-butylene glycoldiacrylate; 1,4-butanediol diacrylate; 1, 6-hexanediol diacrylate;1,9-nonanediol diacrylate; neopentyl glycol diacrylate; polypropyleneglycol #400 diacrylate; EO adduct trimethylol-propane triacrylate;pentaerythritol triacrylate; pentaerythritol tetra acrylate; di-pentaerythritol hexa acrylate; tris acryloyl oxyethyl phosphate; ethyleneglycol dimethacrylate; diethylene glycol dimethacrylate; polyethyleneglycol #200 dimethacrylate; polyethylene glycol #400 dimethacrylate;polyethylene glycol #600 dimethacrylate; 1,4-butanediol dimethacrylate;1,6-hexanediol dimethacrylate; neo pentyl glycol dimethacrylate;polypropylene glycol #400 dimethacrylate; glycerol dimethacrylate;2-hydroxy-1,3-dimethacryloxy propane diacrylate; 2,2-bis[4-(methacryloxy ethoxy) phenyl]propane diacrylate; 2,2-bis[4-(methacryloxy diethoxy) phenyl]propane diacrylate; 2,2-bis[4-(methacryloxypolyethoxy) phenyl]propane diacrylate EO denaturedbisphenol A diacrylate; PO denatured bisphenol A diacrylate trimethylolpropane triacrylate; PO denatured bisphenol A diacrylatetrimethylol-propane trimethacrylate; and 2,2-bis[4-(meth-cryloxydiethoxy) phenyl]propan dimethacrylate, etc.

[0078] As vinyl ether, the followngs can be used; vinyl methyl ether;vinyl ethyl ether; vinyl iso-propyl ether; vinyl iso-butyl ether; vinyln-butyl ether; vinyl n-amyl ether; vinyl iso-amyl ether; vinyl 2-ethylhexyl ether; vinyl n-octadecyl ether; cyanomethyl vinyl ether;2,2-dimethyl aminoethyl vinyl ether; 2-chloroethyl vinyl ether;β-difluoromethyl vinyl ether; benzyl vinyl ether; phenyl vinyl ether;divinyl ether; and divinyl acetal, etc.

[0079] As a polimerizable monomer having an epoxy group, the followingscan be used; glycidyl acrylate, α-methyl glycidyl acrylate, 3,4-epoxycyclohexyl methyl acrylate (Brand name: CYCLOMER A200, made by DaicelChemical Industries, Ltd), glycidyl methacrylate, α-methyl glycidylmethacrylate (Brand name: M-GMA, made by Daicel Chemical Industries,Ltd), and 3,4-epoxy cyclohexyl methyl methacrylate (Brand Name: CYCLOMERM100, Daicel Chemical Industries, Ltd).

[0080] As another monomer in addition to the monomers listed above, thefollowings can be used; styrene, α-methyl styrene, vinyl toluene, vinylacetate, vinyl chloride vinylidene chloride and a compound such as amacromer of AS-6, AN-6 and AA-6 (To a Gosei Co, Ltd) and so on.

[0081] For incorporating a hindered amine group into a polymer, amonomer having a hindered amine group may be copolymerized. One kind ortwo or more kinds of such monomer having a hindered amine may be usedfor copolymerization.

[0082] For incorporating a cycloalkyl group into a polymer, at least onekind of the monomer having a cycloalkyl group as described before may becopolymerized.

[0083] For incorporating a benzotriazol group into a polymer, themonomer having a benzotriazol group as described before may becopolymerized. One kind or two or more kinds of the monomer having abenzotriazol group may be used.

[0084] An acrylic polymer layer, which is made of a polymer obtained bycopolymerizing the aforesaid monomer having a hindered amine group, mayimprove the strength of adhesion between an aluminum foil and anot-drawn film.

[0085] Use of a copolymer, which is obtained by copolymerizing theaforementioned monomer having a cycloalkyl group, allows the acrylicpolymer layer to have an impermeability of steam and a water resistance.

[0086] Use of a copolymer, which is obtained by copolymerizing theaforesaid monomer having a benzotriazol monomer, allows the acrylicpolymer layer to have an impermeability of steam and a water resistance.

[0087] Also, although the present invention does not limit to aparticular range of the content of those monomer, the following rangesare preferable: It is preferable that the content of a monomer having ahindered amine group is defined between 0.1 to 10.0% by weight. It ispreferable that the content of a monomer having a cycloalkyl group isdefined between 5.0 to 97.8% by weight. It is preferable that thecontent of a monomer having a benzotriazol group is defined between 0.1to 50.0% by weight. It is also preferable that a content of anothermonomer in addition to the ones listed above is defined between 2.0 to94.8% by weight. Such contents particularly described here maypreferably make a 100% by weight of polymer.

[0088] Furthermore, as mentioned relating to a polymer constituting theacrylic polymer according to the present invention, it is preferable touse an acrylic polymer having a cycloalkyl group obtained bypolymerizing a monomer component containing at least a monomer having acycloalkyl group, in order to obtain a good property for used as acasing material for a battery.

[0089] Further, it is also preferably to use an acrylic polymer having acycloalkyl group, as well as a hindered amine group and/or abenzotriazol group. Such acrylic polymer may be obtained by polymerizingmonomer components containing a monomer having a cycloalkyl group aswell as a monomer having a hindered amine group and/or a monomer havinga benzotriazol group.

[0090] Each component is mixed in a predetermined content to obtain amixture, which is polymerized by means of one of the known polymerizingmethods to obtain a polymer. Among the known polymerizing methods, it ispreferable to use a method of solution polymerization since it is notrequired to add another solvent to dissolve a polymer into the solventfor application, and in addition that the method may provide a polymersolution without containing an additional component such as surfactantand so on.

[0091] As an organic solvent, the followings can be used. One kind ortwo or more kinds may be used:

[0092] as an aromatic hydrocarbon solvent, such as toluene, xylene,Sorbeso 1000 (by Maruzen Sekiyu Kagaku Co. Ltd), Sorbeso 1500 (byMaruzen Sekiyu Kagaku Co, Ltd), mineral spirit solvents, ethyl acetate,n-propyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate,ethylene glycol ethyl ether acetate (cellosolve acetate), and propyleneglycol mono methyl ether acetate (Arcosolv PMA, by Kuraray Co. Ltd);

[0093] as a ketone solvent, such as acetone, methyl ethyl ketone, methylisobutyl ketone and cyclohexanone;

[0094] as an alcohol solvent, such as methanol, ethanol, n-propylalcohol, isopropyl alcohol, n-butyl alcohol, cyclohexanol, ethyleneglycol, propylene glycol, propylene glycol mono methyl ether (brandname: PGM, by Kuraray Co. Ltd), propylene glycol mono ethyl ether (brandname: PE, by Kuraray Co. Ltd), propylene glycol tertiary butyl ether(brand name: PTB, by Kuraray Co. Ltd), 3-methyl-3-methoxy butanol (brandname: Solfit, by Kuraray Co. Ltd), and dipropylene glycol mono methylether (brand name: D-PGM, by Kuraray Co. Ltd);

[0095] as an ether solvent, such as ethylene glycol mono methyl ether(methyl cellsolve), ethylene glycol mono ethyl ether (ethyl cellosolve),ethylene glycol mono butyl ether (butyl cellosolve), diethylene glycolmono ethyl ether (ethyl Carbitol), and diethylene glycol mono butylether (butyl Carbitol); and

[0096] as another solvent in addition to the solvents as listed above,such as tetrahydrofuran, N, N-dimethyl formamide, dimethyl acetamide,dioxane, chloroform and so on.

[0097] As a polymerization initiator which is useful for the presentinbention, the followings can be used; 2,2′-azobis-(2-ethylbutyronitrile), t-butyl peroxy-2-ethyl hexanoate and so on. Suchpolymerization initiator may be used in a range from 0.05 to 20% byweight, and in particularly from 0.1 to 10% by weight, in the totalweight of the polymerizable monomers.

[0098] As an azo initiator, the followings can be used;2,2′-azobis-(2-methyl butyronitrile) (brand name: ABN-E, by JapanHydrazine Company, Inc.), 2,2′-azobis isobutyronitrile (brand name:AIBN, by Japan Hydrazine Company, Inc.), and 2,2′-azobis (2,4-dimethylvaleronitrile) (brand name: ABN-V, by Japan Hydrazine Company, Inc.).

[0099] As a peroxide initiator, the followings can be used; benzoylperoxide (brand name: Nyper B W, by Nihon Yushi K.K. (NOF Corporation)),1,1-bis (t-butyl peroxy)-3,3,5-trimethyl cyclohexane (brand name:Perhexa 3M, by Nihon Yushi K.K. (NOF Corporation)), and t-butylperoxy-2-ethyl hexanoate (brand name: Perbutyl O, by Nihon Yushi K.K.(NOF Corporation)).

[0100] Such a polymerization initiator as listed above may be used in anamount of 0.05 to 20% by weight, and in particularly of 0.1 to 10% byweight, in the total weight of the polymerizable monomer. It ispreferable that the polymerization reaction is carried out at atemperature approximately between room temperature and 200° C., and inparticular between 40 and 140° C.

[0101] As a chain-transfer agent, the followings can be used; n-dodecylmercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, γ-mercapto propyltrimethoxy silane and so on.

[0102] Each compound may be used alone or in combination. It ispreferable that the compound may be used in an amount of 0.1 to 10% byweight in the total amount of the monomer.

[0103] As a chain-transfer agent, alkyl mercaptans such as n-butylmercaptan, n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan,t-dodecyl mercaptan, cetyl mercaptan and stearyl mercaptan can beexemplified. Also, as another mercaptans in addition to the compound aslisted above, such as thioglycolic acid, thioglycerol, ethylenethioglycol, thioglycolic acid 2-ethyl hexyl, 2-mercapto ethanol,mercapto glycerol, mercapto succinic acid, and mercapto propolonic acidmay be exemplified. In addition, disulfide, dimethylxanthogen disulfide,secondary alcohols, isopropyl alcohol, dioxane, tetrahydrofuran,isopropyl benzole, α-methyl styrene dimer, and2,4-diphenyl-4-methyl-1-pentene may be exemplified. Also, as a halogencompound, carbon tetrachloride, chloroform, trichloro bromo ethane,bromoform and so on may be exemplified.

[0104] Objective properties according to the present invention may beobtained by provision of the acrylic polymer layer between the aluminumfoil layer and the not-drawn film layer. Additionally, crosslinkagetherebetween by reacting with an isocyanate group allows the polymerlayer to have a further property of electrolyte and heat resistance.

[0105] In this case, a polymerizable monomer having a hydroxyl group isa necessary component of a raw material of the polymer, which is reactedwith an isocyanate group. The component may be used in an amount of 2.0to 35% by weight, and in particular of 3.5 to 23% by weight, in themonomer components so as to prepare a copolymer. In case of less than2.0% by weight, the content of the hydrogen group in the resultantpolymer may be too little so that the reactivity with a polyisocyanatemay be decreased, which results in decreasing a crosslinking density.Therefore, it is difficult to obtain a sufficient adhesion, which is oneof the objects of the present invention. On the other hand, in case ofmore than 35% by weight, a stability of storage after incorporating apolyisocyanate may be unstable.

[0106] Therefore, in case where the polymer of an acrylic polymer layeris made of acrylic polyol, it is possible to crosslink an isocyanategroup as described above so as to obtain one of preferable embodiments.In particular, as an acrylic polyol according to the present invention,at least one selected from a group consisting of a polymerizable monomerhaving a hydrogen group may be used.

[0107] As a compound having an isocyanate group used for the abovementioned treatment, any polyisocyanate may be used as long as it hastwo or more isocyanate groups in its molecular. For example,trimethylene diisocyanate, 1,6-hexamethylene diisocyanate, tolylenediisocyanate, xylene diisocyanate, diphenyl methane diisocyanate, andisophorone diisocyanate may be exemplified. Also, a derivative from thatdiisocyanate such as adduct polyisocyanate compound such as trimethylolpropane adduct, biuret compound, and isocyanurate compound may beexemplified. Also, blocked isocyanate compounds, where the isocyanategroup of the isocyanate compounds as above mentioned is blocked byε-caprolactam, phenol, cresol, oxime, alcohol and so on, may beexemplified. One kind or two or more kinds of the compound as mentionedabove may be used into a mixture.

[0108] In this case, the isocyanate group of the polyisocyanate compoundmay be contained in an amount of 0.5 to 2.0 equivalents, and inparticular of 0.8 to 1.5 equivalents, with comparison of 1 equivalent ofthe hydrogen group in the polymer, in order to crosslink.

[0109] It is preferable to use a known catalyst, for example, organictin compound such as dilauric acid di-n-butyl tin (di-n-butyltindilaurate), or tertiary amine or the like, in order to promote thereaction of isocyanate group into an urethane. At the moment when theobtained polymer is applied on an aluminum foil, it is possible tooptionally add a various kind of additives for a paint such as organicsolvent, filler, leveling agent, plasticizer, stabilizer, dye, pigmentand so on.

[0110] Relating to the lamination comprising an aluminum foil and films,which constitutes the casing material of an electronic componentaccording to the present invention, the heat resistant resin drawn filmmay be provided on the both surfaces of the aluminum foil, and isnecessary to be provide at least on the outer layer, which is anopposite side of the aluminum foil having a not-drawn film layer, bydirectly laminating by means of an adhesives. Therefore, there may beless possibility of break or crack by necking of the aluminum foil.

[0111] Between the aluminum foil and the thermoplastic resin not-drawnfilm, a solution may be applied to coat or be subjected to a melt-coator a dry lamination of the film of a polymer to be formed, so as toobtain an acrylic polymer layer.

[0112] The thermoplastic resin not-drawn film is positioned at the mostinside portion of the casing material with the acrylic polymer layer. Inother word, the thermoplastic resin not-drawn film is positioned at theinside of the casing when assembled into a battery casing. Therefore,the thermoplastic resin not-drawn film allows the casing material for anelectronic component to have a heat sealing property as well as toassure chemical resistance of the casing.

[0113] As to laminating, in case of laminating a heat resistant resindrawn film such as polyamide film, it is required to use a dry laminateadhesives, and in particular, an urethane dry laminate adhesives. On theother hand, in case of laminating a thermoplastic resin not-drawn filmof polyethylene, polypropylene, ethyleneacrylate copolymer (EAA),ionomer resin and the like onto an aluminum foil, an acrylic polymerlayer may be used for laminating.

[0114] The casing material for an electronic component according to thepresent invention generally comprises a combination of a heat resistantresin drawn film, an aluminum foil, a polymer layer of acrylic polyoland a thermoplastic resin not-drawn film. According to the presentinvention, the casing material is preferably designed to have a totalthickness of 150 μm or less (including a thickness of a dry laminate).Even if such a thickness, the casing material may accomplish the objectsof the present invention and it is not necessary to have a thicknessmore than that described above. However, the present invention does notlimit thereto and may vary depending on the size of a battery or acapacitor. An excess thickness of the casing material may decrease avolumetric energy density.

[0115] When using the casing material for an electronic componentaccording to the present invention, the casing material may beefficiently and productively pressed to form into a casing by means of acold deep-drawing or overhang method. Also, it is possible to seal by aheat sealing so that the casing material may be pressed to form withoutproviding an specific area or a volume for sealing, which is necessaryfor the prior art material, and the casing for an electronic componentaccording to the present invention has a sharp shape. The casingmaterial according to the present invention also may be prepared to bethin. Consequently, the casing material according to the presentinvention allows to produce a battery or a capacitor having a highvolumetric energy density or a high gravimetric energy density.

[0116] The present invention does not limit to a particular process forpreparing a battery casing, and it may be produced by using a knownprocess. The casing material according to the present invention may bepreferably pressed by a cold (or a room temperature) forming method sothat it is not required to heat at pressing. Therefore, there is no needto be taken into consideration of deorientation of the drawn film due toheating at pressing or of occurrence of delamination between thealuminum foil and the heat resistant resin drawn film due to heatshrinkage of the drawn film. Therefore, the casing material according tothe present invention may be formed into a battery casing havingsharpness and large strength. In case of required to be formed into acasing whose height is larger, it is formed stepwise.

[0117] Further, the casing material for an electronic componentaccording to the present invention has a less directionality in terms ofa mechanical property, so that it has a feature to be pressed withoutlubricating in case of using a overhang method or a deep-drawing methodin which the height of the formed body is lower (in particular, 5 mm orless).

[0118] Also, the casing material for an electronic component is superiorto heat sealing property, chemical resistance, formability and the like.Therefore, the casing material according to the present invention isuseful not only for a battery casing but also for a casing for packagingchemical product, cosmetic, chemical for photograph and the like, whichhas a high corrosiveness or includes an organic solvent.

EXAMPLE

[0119] The invention is now described based on the following presentexamples and comparative examples. However, the present invention is notintended to be limited by the following description. In the followingdescription about the present examples and the comparative examples,“part” means “part by weight” and “%” means “% by weight”

[0120] [Adhesives for an Outer Layer” (Acrylic Polymer)]

Present Example 1

[0121] Into a four inlets flask equipped with a thermometer, a leadingpipe for nitrogen, a dripping funnel, a cooling tube and a stirrer, 55parts of ethyl acetate as a solvent was prepared and heated into 80° C.On the other hand, 3 parts of 4-methacryloyloxy-2,2,6, 6-tetramethylpiperidine as a polymerizable monomer having a hindered amine group, 1part of 2-[2′-hydroxy-5′-(methacryloyloxyethyl) phenyl]-2H-benzotriazole (which is hereinafter referred to as “Benzotriazole (A)”) as apolymerizable monomer having a cycloalkyl group, and 5 parts of hydroxyethyl methacrylate, 30 parts of butyl methacrylate as anotherpolymerizable monomer, 0.5 parts of methacrylic acid as anotherpolymerizable monomer, 20.5 parts of butyl acrylate as anotherpolymerizable monomer, and 0.5 parts of 2,2′-azobis isobutyronitrile asa polymerization initiator (which is hereinafter referred to as“initiator”) were mixed together in a mixture, which was prepared to beput into a dripping funnel. Then the mixture is dripped with duration of2 hours with stirring at 80° C. with flowing nitrogen gas. Further,mixture is kept heated with stirring at 80° C. for 4 hours forcopolymerization.

[0122] Then, with the thereby obtained copolymer solution, a multifunctional isocyanate (Sumidur N-3200; by Sumitomo Bayer Urethane Co,Ltd) as a crosslinking agent was measured to be mixed in such amount asthe equivalent ratio of the isocyanate group to the hydroxyl group was1:1. Further, ethyl acetate was added for dilution to adjust viscositythereof.

[0123] The resultant solution was applied on an aluminum foil andcompulsory dried at 100° C. for 20 seconds, and then a CPP or an ionomerfilm was attached together to obtain a test piece.

[0124] With a mixing ratio shown in table 1, an acrylic polymer wassynthesized in a way similar to the case of Example 1, and incorporateda multi functional isocyanate thereto to obtain a test piece.

Present Examples 1 to 6, and Comparative Example 1

[0125] (A Casing Material for an Electronic Component)

[0126] A heat resistant resin drawn film, a thermoplastic resinnot-drawn film and an aluminum foil of aluminum iron alloy (AA Standard,8079, O-member) was used. Also, an urethane dry laminate adhesives(AD502/CAT10, by Toyo Morton Co, Ltd) was used as an adhesives for anouter layer, and an adhesives of acrylic polymer was used as anadhesives for an inner layer.

[0127] In this specification, the following abbreviations are used.

[0128] 1. Each of the four directions means each of the directions of0°, 45°, 90° and 135° deviated from a tensile direction as standard.

[0129] 2. Al: an aluminum foil

[0130] 3. ON{circle over (1)}: a polyamide film

[0131] [tensile strength: four directions=250 N/mm², 265 N/mm², 250N/mm², and 245 N/mm²]

[0132] [tensile elongation: four directions=162%, 140%, 153%, and 155%]

[0133] 4. ON{circle over (2)}: a polyamide film

[0134] [tensile strength: four directions=188 N/mm², 235 N/mm², 215N/mm², and 195 N/mm²]

[0135] [tensile elongation: four directions=121%, 86%, 99%, and 89%]

[0136] 5. ON{circle over (3)}: a polyamide film

[0137] [tensile strength: four directions=168 N/mm², 135 N/mm², 151N/mm², and 144 N/mm²]

[0138] [tensile elongation: four directions=112%, 66%, 89%, and 67%]

[0139] 6. PET{circle over (1)}: a polyester film

[0140] [tensile strength: four directions=220 N/mm², 245 N/mm², 265N/mm², and 221 N/mm²]

[0141] [tensile elongation: four directions=122%, 90%, 105%, and 98%]

[0142] 7. LLDPE: a linear low density polyethylene film

[0143] 8. CPP: a not-drawn polypropylene film

[0144] 9. IO: an ionomer resin film

[0145] 10. Dry: adhesives for an outer layer (an urethane adhesives)

[0146] Table 1 shows a constituent of monomers constituting an acrylicpolymer provided between an aluminum foil and a not-drawn film. TABLE 1Polymer Adhesive agent Adhesive agent Example Example Example ExampleExample Example Comparative Nos. 1 & 7 No. 2 No. 3 No. 4 No. 5 No. 6Example Adhesive Adhesive Adhesive Adhesive Adhesive Adhesive No. 1agent agent agent agent agent agent Adhesive agent No. 1 No. 2 No. 3 No.4 No. 5 No. 6 No. 7 4-methacryloyloxy-2, 3 0.5 — — 1 1 dry laminate 2,6, 6-tetramethyl adhesives of piperidine (a) urethane cyclohexyl 40 3030 — 30 30 methacrylate (b) 2-[2′-hydroxy-5′- 1 — — — 0.5 1methacryloyloxy ethyl phenyl]-2H- benzotriazole (c) hydroxy ethyl 5 1010 10 2 1 methacrylate butyl methacrylate 20 20 20 20 26 26 methacrylicacid 0.5 0.5 0.5 0.5 0.5 0.5 butyl acrylate 30.5 39 39.5 39.5 40 40.5methyl methacrylate — — — 30 — —

[0147] (Construction of a Laminate Member)

[0148] Present Example 1: ON{circle over (1)}²⁵/Dry/Al⁴⁰/Adhesives1/CPP³⁰ (the total thickness of the casing material: 100 μm)

[0149] Present Example 2: ON{circle over (2)}²⁵/Dry/Al⁴⁰/Adhesives2/IO⁵⁰ (the total thickness of the casing material: 120 μm)

[0150] Present Example 3: ON{circle over (2)}²⁵/Dry/Al⁴⁰/Adhesives3/CPP³⁰ (the total thickness of the casing material 100 μm)

[0151] Present Example 4: PET{circle over (1)}¹⁶/Dry/Al⁴⁰/Adhesives4/CPP³⁰ (the total thickness of the casing material 91 μm)

[0152] Present Example 5: ON{circle over (2)}²⁵/Dry/Al⁴⁰/Adhesives5/CPP³⁰ (the total thickness of the casing material: 100 μm)

[0153] Present Example 6: PET{circle over (1)}¹⁶/Dry/Al⁴⁰/Adhesives6/CPP³⁰ (the total thickness of the casing material: 91 μm)

[0154] Present Example 7: ON{circle over (1)}²⁵/Dry/Al⁴⁰/Adhesives1/LLDPE³⁰ (the total thickness of the casing material: 100 μm)

[0155] Comparative Example 1: ON{circle over (1)}²⁵/Dry/Al⁴⁰/Adhesives7/CPP³⁰ (the total thickness of the casing material: 100 μm)

[0156] (Evaluation Method of the Formability)

[0157] The obtained casing material for an electronic component wasformed into a blank shape having a size of 110 mm×180 mm, and then afirst step forming using a straight metallic mold in which a height ofthe formed body was not defined was carried out. The formability wasevaluated by comparing each of the heights of the formed casingmaterials.

[0158] The metallic mold used here had a punch shape having a longerside of 60 mm, a shorter side of 45 mm, a radius at its corner of 1 to 2mm, a radius at its punch shoulder of 1 mm, and a radius at its dieshoulder of 0.5 mm. The result obtained is shown in Table 1.

[0159] (The Evaluation of The Sealing Property)

[0160] Into a rectangular casing formed as described above, anelectrolyte (dimethyle carbonate+ethyl carbonate (DMC: EC=1:1)+lithiumsalt) was charged, and then heat-sealed. Then, the casing was laid to bestored for 30 days at 60° C. After the storage, whether a leakage of theseal occurred or not was checked. The result is shown in Table 2.

[0161] (Evaluation Method of the Permeability of Steam)

[0162] Into a rectangular casing formed as described above, a batterywas charged, and then heat-sealed. Then, thereby sealed casing wasstored at an atmosphere having 60°×90% RH for 7 days, and then a watercontent of the electrolyte was measured by means of Karl Fisher method.The result is shown in Table 2.

[0163] (Evaluation Method of the Electrolyte Resistance)

[0164] A Strength of the laminate was measured after immersed in anelectrolyte (dimethyl carbonate:ethyl carbonate=1:1+Li salt) for 7 daysat room temperature. TABLE 2 Forming height Sealing Performanceimpermeability impermeability Corner R2 Corner R1 Leaking of steam ofelectrolyte Example 1 ⊚ ◯ No leaking ⊚ ◯ Example 2 ◯ Δ No leaking ⊚ ◯Example 3 ◯ Δ No leaking ⊚ ◯ Example 4 ◯ Δ No leaking ◯ ◯ Example 5 ◯ ΔNo leaking ⊚ ◯ Example 6 ◯ Δ No leaking ⊚ Δ Example 7 ⊚ ◯ No leaking ⊚ ◯Comparative X X No leaking X Δ Example 1

[0165] Also, table 3 shows a standard for evaluating. TABLE 3impermeability of impermeability of Evaluation Formability steamelectrolyte ⊚ 5 mm or more  50 ppm or less Laminating strength: Nochange ◯ 3 to 5 mm  50 to 100 ppm Laminating strength: Remaining rate60% or more Δ 2 to 3 mm 100 to 300 ppm Laminating strength: Remainingrate 30% or more X Less than 2 mm 300 ppm or more Laminating strength:Delaminated

[0166] The casing according to the present invention is superior informability and may be pressed to form into a product having a sharpshape by means of overhang or deep-drawing method. The casing materialis also superior to strength, adhesion between an aluminum and a resinlayer, impermeability of steam and electrolyte, formability, heat sealproperty, and corrosion resistance to an electrolyte. The presentinventors have studied for developing a casing material for anelectronic component having above mentioned properties. The presentinventors have found that the objects may be accomplished by that thecasing material comprising an acrylic polymer layer provided between analuminum foil layer and a not-drawn film layer. Also, the presentinventor has found that a polymer having at least one organic groupselected from a group consisting of hindered amine group, cycloalkylgroup and benzo triazol group, each group having a specific structure,shows an significant property, and to reach the present invention.

[0167] In particular, a heat resistant resin drawn film is provided asan outer layer, and an acrylic polymer layer is provided between analuminum foil and a thermoplastic resin not-drawn film, so that neckingbreak at pressing of the aluminum foil may be avoided. Also, the presentinvention may form a casing having impermeability of steam andelectrolyte, formability, heat seal property, mechanical strength,stability in storage at high temperature, and chemical resistance.

INDUSTRIAL APPLICABILITY

[0168] The present invention is useful for a casing material for anelectronic component for a secondary storage battery, an electronicdouble layer capacitor and so on which is high in volumetric energydensity, gravimetric energy density and efficiency. Also, the presentinvention is useful for a casing material for packaging not only anelectronic component but also a medical product, a cosmetic, a highcorrosive content such as chemical with an organic solvent forphotograph.

1. (amended) a casing material for an electronic component, wherein saidcasing material comprises a heat resistant resin drawn film layer as anouter layer, a thermoplastic resin not-drawn film layer as an innerlayer and an aluminum foil layer provided between said drawn-film layerand said not-drawn film layer, characterized in that: an acrylic polymerlayer is provided between said aluminum foil layer and said not-drawnfilm layer, and said acrylic polymer layer is made of a polymer havingat least one organic group selected from the group consisting ofhindered amine group, cycloalkyl group and benzotriazol group. 2.(Deleted)
 3. (Amended) The casing material for an electronic componentas recited in claim 1, wherein said acrylic polymer layer comprises anacrylic polyol crosslinked with isocyanate.
 4. (Amended) The casingmaterial for an electronic component as recited in claim 1 or 3, whereinsaid aluminum foil layer is made of an O-material of pure aluminum oraluminum iron alloy having a thickness of 7 to 100 μm.
 5. (Amended) Thecasing material for an electronic component as recited in any one ofclaims 1, 3 and 4, wherein said heat resistant resin drawn film layercomprises a drawn film made of polyamide or polyester with a thicknessof 9 to 50 μm.
 6. The casing material for an electronic component asrecited in claim 5, wherein said heat resistant resin drawn film hastensile strength of 150 N/mm² or more in the four directions (0°, 45°,90°, 135°), and tensile elongation of 80% or more.
 7. (Amended) Thecasing material for an electronic component as recited in any one ofclaims 1, 3 to 6, wherein said thermoplastic resin not-drawn film layercomprises a not-drawn film made of a thermoplastic resin selected fromthe group consisting of polyethylene, polypropylene, olefin copolymer,acid denatured compound thereof and ionomer.
 8. (Amended) The casingmaterial for an electronic component as recited in any one of claims 1,3 to 7, wherein said electronic component casing is a battery casing. 9.(Amended) The casing material for an electronic component as recited inany one of claims 1, 3 to 7, wherein said electronic component casing isa capacitor casing.
 10. (Amended) A casing for an electronic componentformed by deep-drawing or overhanging said casing material for anelectronic-component as recited in any one of claims 1, 3 to 7 into apredetermined shape.
 11. (Amended) An electronic component, comprising:an electronic component body; and a casing surrounding said electroniccomponent body, wherein said casing is formed by deep-drawing oroverhanging said casing material for an electronic component as recitedin any one of claims 1, 3 to
 7. 12. The electronic component as recitedin claim 11, wherein said electronic component body is a battery. 13.The electronic component as recited in claim 12, wherein said battery isany one of batteries selected from the group consisting of a lithium ionbattery, a polymer battery, a nickel-hydrogen battery, a primary batteryand a secondary battery.
 14. The electronic component as recited inclaim 11, wherein said electronic component body is a capacitor.
 15. Theelectronic component as recited in claim 14, wherein said capacitor isan electrical double layer capacitor.
 16. (Amended) A packaging materialfor packaging contents which is strong in corrosive such as medicalproduct and cosmetic, chemical for photograph or contents including anorganic solvent, said packaging material comprising: a heat resistantresin drawn-film layer as an outer layer; a thermoplastic resinnot-drawn film layer as an inner layer; and an aluminum foil layerprovided between said layers; wherein an acrylic polymer layer isprovided between said aluminum foil layer and said not-drawn film layer,and wherein said acrylic polymer layer is made of a polymer having atleast one organic group selected from the group comprising hinderedamine group, cycloalkyl group and benzotriazol group.
 17. (Deleted) 18.(Amended) The packaging material as recited in claim 16, wherein saidacrylic polymer layer is made of a polymer which is a polyol crosslinkedwith isocyanate.
 19. (Amended) The packaging material as recited inclaim 16 or 18, wherein said aluminum foil layer comprises an O-membermade of a pure aluminum or an Aluminum iron alloy having a thickness of7 to 100 μm.
 20. (Amended) The packaging material as recited in claim 16or 18, wherein said heat resistant resin drawn film layer comprises adrawn film made of polyamide or polyester with a thickness of 9 to 50μm.
 21. The packaging material as recited in claim 20, wherein said heatresistant resin drawn film has a tensile strength of 150 N/mm² or morein the four directions (0°, 45°, 90°, 135°) and a tensile elongation of80% or more.
 22. (Amended) The packaging material as recited in any oneof claims 16, 18 to 21 wherein said thermoplastic resin not-drawn filmlayer comprises a not-drawn film made of a thermoplastic resin selectedfrom the group including polyethylene, polypropylene, olefin copolymer,acid denatured compound and ionomer.
 23. (Added) The casing material foran electronic component as recited in any one of claims 1, 3 to 9,wherein said acrylic polymer layer is made of a polymer having any oneof organic groups selected from the group consisting of hindered aminegroup and benzotriazol group and cycloalkyl group.
 24. (Added) Thecasing material for an electronic component as recited in any of claims1, 3 to 9, wherein said acrylic polymer layer is made of a polymerhaving cycloalkyl group, hindered amine group and benzotriazol group.25. (Added) The casing material for an electronic component as recitedin claim 24, wherein said acrylic polymer is made an acrylic polymercomprising: a monomer having cycloalkyl group: 5.0 to 97.8% by weight; amonomer having hindered amine group: 0.1 to 10.0% by weight; a momonerhaving benzotriazol group: 0.1 to 50.0% by weigth; and a polymerizablemonomer: 2.0 to 94.8% by weight.
 26. (Added) The packaging material asrecited in any one of claims 16, 18 to 22, wherein said acrylic polymerlayer is made of a polymer having any one of organic groups selectedfrom the group consisting of hindered amine group and benzotriazol groupand cycloalkyl group.
 27. (Added) The packaging material as recited inany one of claims 16, 18 to 22, wherein said acrylic polymer layer ismade of a polymer having cycloalkyl group, hindered amine group andbenzotriazol group.
 28. (Added) The packaging material as recited inclaim 27, wherein said acrylic polymer is made an acrylic polymercomprising: a monomer having cycloalkyl group: 5.0 to 97.8% by weight; amonomer having hindered amine group: 0.1 to 10.0% by weight; a momonerhaving benzotriazol group: 0.1 to 50.0% by weigth; and a polymerizablemonomer: 2.0 to 94.8% by weight.